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Connecting 30 BS2 to one PC ( help please) — Parallax Forums

Connecting 30 BS2 to one PC ( help please)

MarkusMarkus Posts: 22
edited 2006-04-08 17:11 in BASIC Stamp
Hi,


I need to connect 30 basic Stamps to one PC.


PCs have 2 or 3 RS232 com ports only .

I think that USB is the possible solution.

Is this posible ???

Mark

Help please smhair.gif

Comments

  • Chris SavageChris Savage Parallax Engineering Posts: 14,406
    edited 2006-04-04 02:25
    Markus,

    ·· With FTDI Adapters you will certainly be able to add more BASIC Stamps, but I would need to check on the high limit of the BASIC Stamp Editor as far as highest allowed COM Port for programming purposes.· For just serial communication you could do it though.

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    Chris Savage
    Parallax Tech Support
    csavage@parallax.com
  • Mike GreenMike Green Posts: 23,101
    edited 2006-04-04 02:44
    A few thoughts ... You can only use the PC with one Stamp at a time. If you want to use the PC for development, downloading, and debugging of Stamp programs, either have the students bring their Stamp to the PC or make a simple switchbox. You need 30 momentary contact 3PST (3 pole, single throw) switches for the 3 active signals needed for the Stamps (Rx,Tx,ATN) with a common ground. The spring on the switch requires the student and/or the instructor to connect the Stamp to the PC for only a brief time (while they can hold down the switch) and prevents easy connection of two Stamps at the same time.

    If you want a network of 30 Stamps connected to a PC for data transfer purposes, there are articles in Nuts and Volts (look on Parallax's website) on doing a serial network of stamps. For a network this large, I would use RS-485 (twisted pair) drivers for the Stamps and a RS-232 to RS-485 converter for the PC end. See this App Note <http://www.maxim-ic.com/appnotes.cfm/appnote_number/723&gt; from Maxim for using their chips for an RS-232 to RS-485 converter and a 5V Logic to RS-485 converter.
  • MarkusMarkus Posts: 22
    edited 2006-04-04 17:19
    Yes, following your idea,


    I need each Stamp working separately sending data to the PC using
    one FTDI Adapter for each Stamp. There are USB PCI cards ( like the attached with
    six USB ports each ).

    Then I need a Motherboard with 5 PCI slots. And then the problem is solved.

    Am I right ?

    Thanks Mark

    PS: Of course, before, I will load the each BS2 rutine to each Stamp, so I don't need a Basic Stamp Editor with 30 ports.
    confused.gif
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  • Paul Sr.Paul Sr. Posts: 435
    edited 2006-04-04 17:39
    Markus said...

    Then I need a Motherboard with 5 PCI slots.

    Why? You can "chain" up to 127 USB devices. One card is sufficient.
  • MarkusMarkus Posts: 22
    edited 2006-04-04 19:41
    Sorry Pwssr:


    But I don't understand.

    Could you explain please?

    Thanks, Mark
  • Paul BakerPaul Baker Posts: 6,351
    edited 2006-04-04 20:09
    Multiple USB devices can be connected to a single USB channel. All that is needed is powered USB hub(s) connected to the port. A device such as this one: http://www.nextag.com/serv/main/buyer/ProductM.jsp?nxtg=1bf70a1c0534-6C17290FE5CC6E5B&page=1&pdir=3&lgnode=300000&display_mode=0&node=300000&lgsearch=usb_hub&ptitle=68526600&core=&kw=Iogear_7_Port_USB

    would work, you would need 5 of them. one would be plugged into the computer and 4 would be plugged into the one plugged into the computer. The 4 second teir hubs would provide 28 connections and there would be·3 additional ports on the 1st tier hub for a total of 31 connections to devices availible.

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  • Paul Sr.Paul Sr. Posts: 435
    edited 2006-04-04 21:02
    Paul Baker said...
    Multiple USB devices can be connected to a single USB channel. All that is needed is powered USB hub(s) connected to the port. A device such as this one: http://www.nextag.com/serv/main/buyer/ProductM.jsp?nxtg=1bf70a1c0534-6C17290FE5CC6E5B&page=1&pdir=3&lgnode=300000&display_mode=0&node=300000&lgsearch=usb_hub&ptitle=68526600&core=&kw=Iogear_7_Port_USB


    would work, you would need 5 of them. one would be plugged into the computer and 4 would be plugged into the one plugged into the computer. The 4 second teir hubs would provide 28 connections and there would be 3 additional ports on the 1st tier hub for a total of 31 connections to devices availible.

    Thanks Paul - I just got home and you saved me some typing!

    Paul
  • allanlane5allanlane5 Posts: 3,815
    edited 2006-04-04 23:08
    This may have changed with 'modern' Windows, but Window NT 4.0 limited you to ONLY 16 RS-232 ports.

    This sounds like a wonderful opportunity to implement a simple, daisy-chain network of BS2's. You didn't say how far apart they all are. If they're within 10 feet, you sould be able to use the 'open' baud mode to make a 'party-line' network.
  • MarkusMarkus Posts: 22
    edited 2006-04-05 01:48
    Thanks Paul Baker and Allanlane5:

    But then my idea is similar or the same, it is like your idea, because
    I posted this:

    " I need each Stamp working separately sending data to the PC using
    one FTDI Adapter for each Stamp. There are USB PCI cards ( like the attached with
    six USB ports each ).

    Then I need a Motherboard with 5 PCI slots. And then the problem is solved. "

    Then, Paul, if you see the attacment, you can see a USB PCI card that must be installed at the PC.

    Do you know if there is a difference betwen your solution and my solution ?
    Thanks: Mark.

    And allanlane5 :
    Are you sure that it is only 16 RS-232 USB ports ?

    Thanks again: Mark
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  • Robert KubichekRobert Kubichek Posts: 343
    edited 2006-04-05 02:02
    Markus said...
    Hi,


    I need to connect 30 basic Stamps to one PC.


    PCs have 2 or 3 RS232 com ports only .

    I think that USB is the possible solution.

    Is this posible ???

    Mark

    Help please smhair.gif

    Do the stamps Have to be a specific type?
    If you can use the BS2p(e) then you can use a 1wire network.

    Or with RS 232-485, using any of the BS2 stamps you can network them and use a poll and answer for each stamp based on a unique id assigned to that stamp...

    Bob N9LVU scool.gif
  • steve_bsteve_b Posts: 1,563
    edited 2006-04-05 12:37
    Do you need to see each STAMP's data at the same time?
    You could build a giant 16port RS232 buffer box..... Basically, each stamp sends their data which is held in a buffer (1 buffer for each separate stamp), then you could have a PC connected to a stamp that will then go to each buffer and ask for its data. The stamp at the PC could literally "STAMP" the data with the buffer line it received the data from, and then pass it through to the PC.

    It's an idea, not something I've done....and I don't know how readily available these 'buffers' are, or even what to use! I'm banking on someone else having some input on this! tongue.gif

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    ·

    Steve

    "Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."
  • allanlane5allanlane5 Posts: 3,815
    edited 2006-04-05 17:34
    Yes, I'm sure Windows NT 4.0 will support only 16 'COM' ports.

    Now, Windows XP, I don't know.
  • MarkusMarkus Posts: 22
    edited 2006-04-05 19:16
    Thanks Allanlane5,

    Then , If Windows NT 4.0 will support only 16 'COM' ports., ( as you tell me) then it is impossible
    to plug 30 Basic Stamps on a PC running Windows NT 4.0 .


    Paul Baker and Chris Savage: It seems that it is impossible to run
    multiple USB devices working under WIN NT 4.0


    Somebody knows if Windows 98, Windows 2000 and Windows XP could work
    with more than 16 COM ports?

    Thanks for the help. Mark

    PS:
    I need the 30 Stamps working at the same time, then
    the idea of a buffer box isn't a good solution in this case.

    confused.gifconfused.gif
  • SteelSteel Posts: 313
    edited 2006-04-05 23:06
    COM ports and USB ports are different.· You can only address 16 COM ports.· USB Devices can be daisy chained through hubs to have a total of 127 devices.· The PC addresses each one separately.

    I am sort of questioning the big picture here...generally when people have ideas like this one, there is a Much more simple solution.

    Another solution is to use 1 BS2 as a 'motherboard'
    ·-Connect this BS2 to the PC Comport.
    ·-Connect 30 BS2s to the motherboard (only 3 wires to connect each, instead of buying USB Cables and Chips)
    ·-In your software, create a com protocol to send messages to each of the 30 BS2's...

    ...Wait a minute...Are you doing a mass manufacturing setup to program 30 BS2's ata atime?
  • CHIPKENCHIPKEN Posts: 45
    edited 2006-04-08 01:34
    The way to do this is to use the parallel port (printer port) as a switching device on a serial port. This was done on a Parallax product known as PCSTAMPII. I think you can connect eight(8) BASIC Stamps·with one parallel port and one serial port.

    Chuck
  • MarkusMarkus Posts: 22
    edited 2006-04-08 16:43
    Thanks Steel:

    I don't understand the meaning of "daisy chained" , but I would like to understand if

    this works:

    -One·PC with 5 PCI slots.

    -Five USB PCI Cards ( Each card with 6 USB connectors)

    ·Here, the total is 30 USB connectors.

    Thanks,
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2006-04-08 17:11
    Daisy Chained is equal to parallel wiring.

    It really is that simple. I believe that each USB port is assigned a unique address and can easily be recognized from the others [noparse][[/noparse] something like·127 ports total]. So 30 should just be able to hang off of one computer port.

    You can buy USB 'hubs' that are something similar in princiiple to the adapter that allows you to plug in 3 household devices into one 120AC outlet.
    I have one that changes one USB into 4, but they come in various sizes and shapes.

    Use bigger devices - 7 or 8 or more ports - to reduce the problems of poor connections.

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    ······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan

    Post Edited (Kramer) : 4/8/2006 5:16:32 PM GMT
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